Existing transport refrigeration systems are used to cool containers, trailers, and other similar transport units. Modern containers may be efficiently stacked for shipment by ship or rail. When containers are shipped by a truck, a single container is placed on a container chassis. When cargo in the container includes, for example, perishable products (e.g. food product, flowers, etc.), the temperature of the container may be controlled to limit loss of the cargo during shipment.
Some existing transport units may include a generator set that supplies power to temperature-controlling components of the transport refrigeration system. These generator sets are typically attached directly to the container or container chassis, and include an engine to power a generator, as well as a fuel container to supply fuel to the generator sets.
Generator sets may operate at a single, relatively constant speed to produce a relatively constant output frequency (e.g. 60 Hz) and one or more output voltages (e.g., ˜230/460 VAC, etc.). These generator sets may operate at the same single speed regardless of the load on the transport refrigeration system. Therefore, the transport refrigerant system may not operate at the most fuel efficient condition for a particular load of the transport refrigeration system. During an extended period of time without inspection by, for example, transportation workers, these generator sets may use up the fuel in the fuel container. The out-of-fuel condition can cause loss of power to the transport refrigeration system, and may result in loss of the perishable cargo. This is especially true when ambient temperature conditions are relatively hot or relatively cold.